U.S. patent number 6,256,594 [Application Number 09/131,997] was granted by the patent office on 2001-07-03 for machine fault monitoring apparatus and method.
This patent grant is currently assigned to Komatsu, Ltd.. Invention is credited to Jiro Akagi, Sadachika Akiyama, Nobuki Hasegawa, Kunihiko Imanishi, Kazunori Kuromoto, Taku Murakami, Takao Nagai, Shigeru Yamamoto.
United States Patent |
6,256,594 |
Yamamoto , et al. |
July 3, 2001 |
Machine fault monitoring apparatus and method
Abstract
Only snapshot data necessary for monitoring faults are collected
from machine such as vehicles, allowing faults to be more
accurately monitored, and the amount of data and the memory storage
volume at a monitoring station to be reduced. The values of a
plurality of (A), (B), (C), and (D) operating parameters (engine
rotational speed, lever operating position, vehicle speed, and
tractive force) which change during the operation of the machine
are sequentially detected for each machine. The fault detection
history data are thus updated every time a fault (drop in engine
oil pressure, overheating) is detected during the operation of the
machine. Thus, when a fault (drop in engine oil pressure) is
detected during the operation of the machine, it is determined on
the basis of the history data whether or not to send to the
monitoring station the sequential values of the operating
parameters ((A) engine rotational speed, (B) lever operating
position, (C) vehicle speed, (D) tractive force) from within a
prescribed period of time (from 10 min. before to 5 min. after)
around the point in time t0 at which the fault was detected. When
it is determined that they should be sent, the type of detected
fault (0001 (drop in engine oil pressure)), the values detected
((A) 2, (B) 3, (C) 3, (D) 2) at the time the fault was detected, as
well as the sequential values of the operating parameters from
within a prescribed period of time (from 10 min. before to 5 min.
after) around the time the fault was detected are transmitted to
the monitoring station. When it is determined that they should not
be sent, on the other hand, the type of detected fault (0001 (drop
in engine oil pressure)) and the values detected ((A) 2, (B) 3, (C)
3, (D) 2) at the time the fault was detected are sent to the
monitoring station.
Inventors: |
Yamamoto; Shigeru (Hirakata,
JP), Imanishi; Kunihiko (Hirakata, JP),
Nagai; Takao (Minami-Saitama-gun, JP), Akiyama;
Sadachika (Yuki, JP), Akagi; Jiro (Oyama,
JP), Hasegawa; Nobuki (Meguro-ku, JP),
Kuromoto; Kazunori (Yokohama, JP), Murakami; Taku
(Yamato, JP) |
Assignee: |
Komatsu, Ltd. (Tokyo,
JP)
|
Family
ID: |
16751152 |
Appl.
No.: |
09/131,997 |
Filed: |
August 11, 1998 |
Foreign Application Priority Data
|
|
|
|
|
Aug 15, 1997 [JP] |
|
|
9-220440 |
|
Current U.S.
Class: |
702/185; 702/184;
702/188; 701/30.4; 701/33.4 |
Current CPC
Class: |
G07C
5/008 (20130101); G05B 23/0264 (20130101); G07C
5/0808 (20130101); G05B 2223/06 (20180801) |
Current International
Class: |
G05B
23/02 (20060101); G07C 5/08 (20060101); G07C
5/00 (20060101); G21C 017/00 (); G06F 011/30 ();
G01M 017/00 () |
Field of
Search: |
;702/35,36,81,84,113,179,180,181,182-186,187,188,33,34,42,43,56,75,114,115,122
;701/29,34,35 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Assouad; Patrick
Assistant Examiner: Barbee; Manuel L.
Attorney, Agent or Firm: Welsh & Katz, Ltd.
Claims
What is claimed is:
1. A machine fault monitoring apparatus having, for each of a
plurality of machines, fault detection means for detecting various
faults occurring during the operation of the machines, and remote
monitoring station for monitoring operating status of the plurality
of machines by collecting fault detection data locally detected by
the fault detection means of the plurality of machines, wherein
each machine comprises:
operating parameter detection means for locally sequentially
detecting various types of operating parameter values which change
during the operation of said machine;
history data update means locally updating fault detection history
data every time a fault is detected by said fault detection means
during the operation of said machine;
determination means for locally determining, based on said history
data and the value of the fault, whether or not to transmit to said
monitoring station sequential values of the operating parameters
within a specified period of time around a point in time at which
the fault was detected, in cases where said fault was detected by
said fault detection means during the operation of said
machine;
transmission means for transmitting to said remote monitoring
station, in cases where it has been determined locally by said
determination means that a transmission should be made, a type of
fault that was detected, a value detected by said operating
parameter detection means at the point in time at which the fault
was detected, as well as the sequential values of said operating
parameters within the specified period of time around the point in
time at which the fault was detected, and also for transmitting to
said remote monitoring station, in cases where it has been
determined by said determination means that no transmission should
be made, the type of fault that was detected and the value detected
by said operating parameter detection means at the point in time
the fault was detected.
2. The machine fault monitoring apparatus according to claim 1,
wherein said transmission means searches for a frequency of the
detected fault based on said history data, and transmits data
indicating the fault frequency to said remote monitoring
stations.
3. A vehicle fault monitoring apparatus having, for each of a
plurality of vehicles, fault detection means for locally detecting
various faults occurring during the operation of the vehicles, and
a remote monitoring stations for monitoring operating status of the
plurality of vehicles by collecting fault detection data detected
by the fault detection means of the plurality of vehicles, wherein
each vehicle comprises:
operating parameter detection means for locally sequentially
detecting various types of operating parameter values which change
during the operation of said vehicle;
history data update means for locally updating fault detection
history data every time a fault is detected by said fault detection
means during the operation of said vehicle;
transmission determination means for locally determining based on
said history data and the value of the fault, whether or not to
transmit to said remote monitoring stations sequential values of
the operating parameters within a specified period of time around a
point in time at which the fault was detected in cases where said
fault was detected by said fault detentions means during the
operation of said vehicle; and
fault data transmission means for transmitting to said remote
monitoring stations, in cases where it has been determined by said
transmission determination means that a transmission should be
made, a type of fault that was detected, a value detected by said
operating parameter detection means at the point in time at which
the fault was detected, as well as the sequential values of said
operating parameters within the specified period of time around the
point in time at which the fault was detected, and also for
transmitting to said remote monitoring station, in cases where it
as been determined by said transmission determination means that no
transmission should be made, the type of fault that was detected
and the value detected by said operating parameter detection means
at the point in time the fault was detected; and wherein said
remote monitoring station comprises:
relation data generating means for accumulating the type of fault
transmitted from each vehicle and the various operating parameter
values at the time the fault was detected, so as to generate data
that relate the types and values of the operating parameters with
the fault;
relation determination means for collating said relation data with
the type of fault transmitted from said vehicle and the values of
the various parameters at the time the fault was detected to
determine whether or not the fault is related to the types and
values of the operating parameters; and
requested signal transmission means for transmitting to the
vehicle, in cases where no relation was determined by said relation
determination means, a signal requesting that values detected by
said operating parameter detection means to be transmitted to said
monitoring stations for a given period of time.
4. The vehicle fault monitoring apparatus according to claim 3,
wherein said fault data transmission means searches for a frequency
of the detected faults based on said history data, and transmits
data indicating the fault frequency to said remote monitoring
stations.
Description
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to an apparatus for monitoring
machine faults based on the operating status of machine such as
construction machine, and more particularly to an apparatus
allowing the amount of data to be reduced when operating status
data are collected at a monitoring station to monitor faults based
on such data.
2. Description of the Related Art
U.S. Pat. No. 5,400,018 is an example of an invention relating to
the surveillance of faults such as drops in vehicle engine oil
pressure or overheating based on the operating status of vehicles
such as construction machine.
In this document, to monitor vehicle faults, data relating to the
operating status from a vehicle are collected at a monitoring
station, and a determination is made, on the basis of the collected
data, whether or not to deal with the fault by repairing the
vehicle, issuing an emergency stop command, or the like.
That is, when a fault such as a drop in engine oil pressure is
detected in a vehicle, a fault (drop in engine oil pressure) code
is generated, and the fault code is transmitted to a monitoring
station. The monitoring station monitors a plurality of vehicles,
and stores vehicle history data for each vehicle, such as the type
of faults occurring in the past, the frequency of such faults, and
the date on which they occurred.
When a fault code is transmitted from a vehicle, it is compared
with the aforementioned vehicle history data. When it is determined
that the fault code indicates an infrequently occurring fault (drop
in engine oil pressure), a snapshot data request command is issued
to the corresponding vehicle to conduct a detailed search of the
status prevailing at the time the fault occurred so as to send
snapshot data from around the time the fault occurred to the
monitoring station. In cases where the fault indicated by the fault
code is frequently occurring, snapshot data from when this type of
fault has occurred will already have been stored at the monitoring
station, and no request command is sent to the corresponding
vehicle, on the assumption that the data are not significant.
Here, "snapshot data" refers to data from around a prescribed
period of time at the time the fault is detected in a vehicle,
which are the data of the vehicle operating parameters (engine
rotational speed, speed, etc.) relating to the fault (such as a
drop in engine oil pressure).
The vehicle receiving the request command transmits snapshot data
from around the point in time at which the fault was detected to
the monitoring station.
Thus, in conventional inventions, in cases where the same
malfunction frequently occurs in the same machine, no snapshot data
are requested of the vehicle so as to minimize the accumulation of
data in the monitoring station.
In the aforementioned conventional technique, however, it is
possible that snapshot data necessary for monitoring faults will be
overlooked by the monitoring station because the determination as
to whether or not snapshot data are needed is made merely by
comparing the vehicle history data in which the type, frequency,
date and the like of the fault indicated by the fault code are
recorded in time sequence. It is also possible, on the other hand,
that snapshot data which are not needed for monitoring faults will
be requested.
That is, even though the same type of fault may have occurred
frequently in the past, the circumstances under which it occurs
vary, and the same fault is not necessarily produced under the same
operating circumstances. Thus, even though the same fault may have
occurred numerous times in the past under the same operating
circumstances without impeding actual operations, the same fault
occurring under different operating circumstances can fatally
damage the vehicle. When, therefore, the need for snapshot data is
determined solely on the basis of the past frequency of the fault,
there is a risk that the vehicle could sustain major damage because
of the inability to collect scarce snapshot data indicating the
potential for fatal damage to the vehicle.
SUMMARY OF THE INVENTION
The invention is intended to solve such problems by transmitting,
in addition to a fault code, a status code which indicates the
status at the time a fault occurs, from the vehicle to the
monitoring station, thereby allowing the monitoring station to make
more accurate determinations as to whether or not snapshot data
should be requested, allowing only snapshot data necessary for
monitoring faults to be collected from the vehicle, and allowing
faults to be monitored in a more reliable manner. The present
invention is also intended to solve such problems by making it
possible to collect only snapshot data necessary for monitoring
faults from vehicles, thereby minimizing the amount of data and the
memory storage volume in the monitoring station.
The first of the present inventions is a machine fault monitoring
apparatus having, for each of a plurality of machines, fault
detection means for detecting various faults occurring during the
operation of the machines, and a monitoring station for monitoring
operating status of the plurality of machines by collecting fault
detection data detected by the fault detection means of the
plurality of machines, wherein each machine comprises:
operating parameter detection means for sequentially detecting
various types of operating parameter values which change during the
operation of said machine;
history data update means for updating fault detection history data
every time a fault is detected by said fault detection means during
the operation of said machine;
determination means for determining, based on said history data,
whether or not to transmit to said monitoring station sequential
values of the operating parameters within a specified period of
time around a point in time at which the fault was detected, in
cases where said fault was detected by said fault detection means
during the operation of said machine; and
transmission means for transmitting to said monitoring station, in
cases where it has been determined by said determination means that
a transmission should be made, a type of fault that was detected, a
value detected by said operating parameter detection means at the
point in time at which the fault was detected, as well as the
sequential values of said operating parameters within the specified
period of time around the point in time at which the fault was
detected, and also for transmitting to said monitoring station, in
cases where it has been determined by said determination means that
no transmission should be made, the type of fault that was detected
and the value detected by said operating parameter detection means
at the point in time the fault was detected.
In the second of the present inventions, in addition to the
structure of the first invention, said monitoring station
comprises:
relation data generating means for accumulating the type of faults
transmitted from each machine and the various operating parameter
values at the time the fault was detected, so as to generate data
that relate the types and values of the operating parameters with
the fault;
relation determination means for collating said related data with
the type of fault transmitted from said machine and the values of
the various parameters at the time the fault was detected to
determine whether or not the fault is related to the types and
values of the operating parameters; and
request signal transmission means for transmitting to the machine,
in cases where no relation was determined by said relation
determination means, a signal requesting that values detected by
said operating parameter detection means be transmitted to said
monitoring station for a given period of time.
According to the structure of the first invention, as shown in FIG.
4, various operating parameters A, B, C, and D (engine rotational
speed, lever operating position, vehicle speed, tractive force),
which change during the operation of the machine, are sequentially
detected in each machine.
As shown in FIG. 3, the fault detection history data are updated
every time a fault (drop in engine oil pressure, overheating) is
detected during the operation of the machine.
As shown in FIG. 6, in cases where a fault (drop in engine oil
pressure) is detected during the operation of the machine, a
determination is made, on the basis of the history data, as to
whether or not to send to the monitoring station the sequential
values of the operating parameters ((A) engine rotational speed,
(B) lever operating position, (C) vehicle speed, and (D) tractive
force) in a prescribed period of time (from 10 min. before to 5
min. after) from around the point in time at which the fault was
detected.
As shown in FIG. 5, when it is determined that a signal should be
sent, the type of detected fault (0001 (drop in engine oil
pressure)), the values ((A) 2, (B) 3, (C) 3, and (D) 2) detected at
the point in time that the fault was detected, as well as the
sequential values of the operating parameters in a prescribed
period of time (from 10 min. before to 5 min. after) from around
the point in time at which the fault was detected are sent to the
monitoring station. When it is determined that no signals should be
sent, the type of detected fault (0001 (drop in engine oil
pressure)) and the values ((A) 2, (B) 3, (C) 3, and (D) 2) detected
at the point in time that the fault was detected are sent to the
monitoring station.
In the second invention, as shown in FIG. 7, the type of fault
(0001 (drop in engine oil pressure)) sent from each machine and the
values (Cd5, Cd8, etc.) of the various operating parameters at the
time the fault was detected accumulate in the monitoring station,
and data relating the fault (0001 (drop in engine oil pressure))
and the operating parameter type and values (Cd5, Cd8, etc.) are
produced.
The type of fault (0001 (drop in engine oil pressure)) sent from
the machine and the various parameter values (Cd8) at the time the
fault was detected are compared with the relation data to determine
whether or not there is any relation between the type of fault
(0001 (drop in engine oil pressure)) and the operating parameter
type and values (Cd8) (whether or not the number of incidents N is
greater than .alpha.).
When it is determined that there is no relation (when the number of
incidents N is no more than .alpha.), a request signal is sent to
the corresponding vehicle to transmit to the monitoring station the
values of the operating parameters ((A) engine rotational speed,
(B) lever operating position, (C) vehicle speed, and (D) tractive
force) detected in a prescribed period of time (from 10 min. before
to 5 min. after).
Thus, according to the structure of the first invention, the need
for snapshot data is not determined solely on the basis of the
fault code from the vehicle indicating the type of fault, as in the
past, but the determination is also made with the addition of the
operating parameter values ((A) 2, (B) 3, (C) 3, and (D) 2)
detected at the point in time at which the fault was detected, so
the need for snapshot data can be determined on the basis of not
only the frequency with which the fault has occurred, as in the
past, but also on the basis of the frequency of the operating
status prevailing at the time the fault has occurred, allowing
requests to be determined more accurately and allowing only data
needed for monitoring faults to be requested from the machines more
accurately.
According to the structure of the second invention, data relating
the type of fault with the types and values of the operating
parameters are produced, and the need for snapshot data is more
accurately determined by comparing the data received from the
machine with the relation data. In other words, the need for
snapshot data is determined not only on the basis of the frequency
of the fault, as in the past, but also on the basis of the degree
to which the fault is related to the operating status at the time
of the fault (the frequency of the operating status or the like),
allowing requests to be determined more accurately and allowing
only data needed for monitoring faults to be requested from the
machines more accurately.
As described above, the first and second inventions make it
possible to collect from the vehicles only the snapshot data needed
for monitoring faults, to more accurately monitor faults, and to
reduce the amount of data and the memory storage volume in the
monitoring station.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a flow chart showing the processing procedure in the
embodiments of the machine fault monitoring apparatus and method of
the present invention, the details of which are carried out on the
vehicle side;
FIG. 2 is a flow chart showing the processing procedure in the
embodiments of the machine fault monitoring apparatus and method of
the present invention, the details of which are carried out on the
computer side;
FIG. 3 schematically depicts details of vehicle fault history
data;
FIG. 4 illustrates status codes;
FIG. 5 illustrates the protocol for data transmitted from a
vehicle;
FIG. 6 is a diagram used to describe snapshot data, and is a time
chart showing the changes in engine rotational speed over time;
FIG. 7 is a graph depicting the status code distribution; and
FIG. 8 is a diagram used to describe the communications networks in
the embodiments.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
Embodiments of the machine fault monitoring apparatus of the
present invention are described below with reference to the
drawings.
A method for monitoring faults which can occur during the operation
of the machine based on the present invention is described
first.
The embodiments assume construction machine as the machine, and
assume an apparatus for supervising and monitoring overhaul periods
and the life of the construction machine, for ensuring that the
construction machine is stopped in emergencies when a major fault
(malfunction) occurs, and for conducting maintenance (inspections,
repairs, etc.) according to the status of the fault occurrence.
Monitoring equipment for bringing this about is constructed in the
following manner.
That is, sensors for sensing the various operating parameter values
which gradually change during the operation of the machine are
suitably disposed in the various parts of construction machine such
as bulldozers to monitor the engine oil pressure P, engine
rotational speed Ne, lever operating position S, vehicle speed v,
tractive force W, engine power (engine output), torque, load
exerted on various working devices, stroke of the hydraulic
cylinders of various working devices, engine blowby pressure in the
oil pressure drive circuit, governor lock position, and the
like.
When these sensors are commonly used sensors (such as engine
rotational speed sensors) for obtaining control feedback signals
when the construction machine is driven and controlled, the
existing sensors can be used as such, without installing new
sensors for monitoring. New sensors for sensing the operating
parameters must be installed to monitor operating parameters that
are not normally used (such as blowby pressure) when construction
machine is driven and controlled.
The detection signals from these sensors are input to a monitoring
controller composed primarily of a CPU, the prescribed processing
is executed by the controller, and the processed results are
displayed on a display device disposed in a location visible to the
operator. Controllers inside the construction machine and a
personal computer 21 outside the construction machine may be
connected by prescribed communications means to allow the results
of the controller processing to be seen at a prescribed external
location (display device of the monitoring station 20).
FIG. 8 shows communications networks 40 and 50 assumed in the
embodiments. The communications networks 40 and 50 are designed to
communicate maintenance information for all types of construction
machine (such as bulldozers, dump trucks, wheel loaders, and
hydraulic shovels) delivered throughout the world, and to provide
the maintenance information to individual users.
That is, as shown in FIG. 8, the communications networks 40 and 50
are generally composed of a field net 40, which is a communications
network among a work site 30 of individual users of the
construction machine, and a global net 50, which is a
communications network between construction machine manufacturers,
businesses, and plants (parts warehouses, repair plants, and
assembly plants) located throughout the world.
The field net 40 comprises a field work site monitoring system in
which a number of bulldozers, dump trucks, wheel loaders, and
hydraulic shovels (referred to as vehicles for the sake of
convenience below) 10, 11, 12, 13, etc. are supervised and
monitored by a monitoring station 20 in a mining or other field
work site 30. The vehicles in the work site 30 may be manned or
unmanned.
In this field work site monitoring system, data indicating the
positional relations between vehicles are transmitted and received
by means of inter-vehicle communications E, F, G, H, and I, while
data indicating travel, stops, or the like from the monitoring
station 20 to the plurality of vehicles 10 etc. as well as vehicle
data from the plurality of vehicles 10 etc. to the monitoring
station 20 are transmitted and received by means of communications
between the vehicles and monitoring station A, B, C, and D.
The monitoring station 20 is provided with a computer 21 having the
function of comprehensive control over the vehicles in the work
site 30.
The global net 50 is composed of a host computer 51 for the
comprehensive supervision of maintenance data related to all the
construction machine (vehicles) delivered by construction machine
manufacturers throughout the world; corporate computers 52 and 53
or subsidiary computer 54, which are subsidiary to the host
computer 51; a construction machine assembly plant (repair plant)
computer 55 and parts warehouse computer 56, which are subsidiary
to the computer 52; construction machine assembly plant (repair
plant) computers 57 and 58, which are subsidiary to computer 53;
and construction machine assembly plant (repair plant) computer 59
and parts warehouse computer 60, which are subsidiary to computer
54.
Mutual communications J are carried out, for example, between the
aforementioned construction machine assembly plant computer 55 and
the computer 21 at the work site 30 of the construction machine
delivered from the construction machine assembly plant.
The data of the computer 21 at the work site 30 are thus input
through communications J and communications in the global net 50 to
the host computer 51, and the data of the host computer 51 are
input through communications in the global net 50 and
communications J to the computer 21 at the work site 30.
The processing executed by these communications networks 40 and 50
is described below with reference to the flow charts depicted in
FIGS. 1 and 2.
FIGS. 1 and 2 show the contents of the communications processing
executed by the monitoring station 20 between the vehicles 10 etc.
and the host computer 51.
FIG. 1 is a flow chart showing the processing procedure executed by
the controller for the vehicle 10 such as a bulldozer.
First, in step 101, when a fault is detected in the vehicle 10
during the operation of vehicle 10, a process is executed to
generate a fault code indicating the type of fault detected.
That is, the values of a set of operating parameters which
gradually change are detected during the operation of the
construction machine.
Here, the set of operating parameters is a set of mutually related
parameters, consisting of primary parameters and subsidiary
parameters.
The following are examples of such sets:
1) engine oil pressure and engine rotational speed, operating lever
operating position, vehicle speed, and tractive force;
2) engine rotational speed and torque;
3) load exerted on working devices, and the stroke of the hydraulic
cylinders of working devices; and
4) engine blowby pressure, engine rotational speed, and governor
lock position.
Here, in the case of the set in 1) above, the engine oil pressure
is the primary parameter, and the engine rotational speed,
operating lever operating position, vehicle speed, and tractive
force are parameters subsidiary to the primary parameter.
It is determined that a fault has occurred when the detected engine
oil pressure P, which is the primary parameter, falls below a
prescribed threshold for a continuous prescribed period of time,
and a fault code ("0001") corresponding to that type of fault (drop
in engine oil pressure) is generated (step 101).
Here, fault generation history data are stored in the memory of the
controller for the vehicle 10.
As shown in FIG. 3, the fault history data consist of data relating
the dates on which a fault occurred and the fault occurrence status
with the type of fault, and are compiled in time sequence.
The type of fault is displayed in fault code, such as 0001 (drop in
engine oil pressure) or 0003 (over heating), and the fault
occurrence status is displayed by symbols for the values of the
subsidiary operating parameters at the time the fault occurred.
This is referred to as the status code.
Here, the subsidiary parameters of a fault with a fault code of
0001 indicating a drop in engine oil pressure P (primary
parameter), as shown in FIG. 4, are the (A) engine rotational speed
Ne, (B) operating lever operating position S, (C) vehicle speed v,
and (D) tractive force, and the values for these operating
parameters (A) engine rotational speed Ne, (B) operating lever
operating position S, (C) vehicle speed v, and (D) tractive force
are hierarchically divided.
The engine rotational speed Ne is divided into Ne<Ne1(such as
1000 rpm), Nel.ltoreq.Ne.ltoreq.Ne2 (such as 1500 rpm), and
Ne>Ne2. The engine rotational speed Ne is displayed as "1" when
it is in the range Ne<Ne1, as "2" when it is in the range
Ne1.ltoreq.Ne.ltoreq.Ne2, and as "3" when it is in the range
Ne>Ne2.
Similarly, the lever operating position S is divided into blade
ascending position, blade descending position, blade left tilt
position, blade right tilt position, ripper ascending position, and
ripper descending position. The lever operating position S is
displayed as "1" when it is in the blade ascending position, as "2"
when it is in the blade descending position, as "3" when it is in
the blade left tilt position, as "4" when it is in the blade right
tilt position, as "5" when it is in the ripper ascending position,
and as "6" when it is in the ripper descending position. When the
operating lever is an electrical lever, the lever operating
position S can be detected based on the output of a potentiometer
for detecting the operation of the electrical lever.
Similarly, the vehicle speed v is divided in to v<v1,
v1.ltoreq.v.ltoreq.v2, and v>v2. The vehicle speed v is
displayed as "1" when it is in the range v<vl, as "2" when it is
in the range v1.ltoreq.v.ltoreq.v2, and as "3" when it is in the
range v>v2.
Similarly, the tractive force W is divided into W<W1,
W1.ltoreq.W.ltoreq.W2, and W>W2. The tractive force W is
displayed as "1" when it is in the range W>W1, as "2" when it is
in the range W1.ltoreq.W.ltoreq.W2, and as "3" when it is in the
range W>W2.
Thus, in FIG. 3, the status code (A) 2 (B) 3 (C) 2 (D) 3
corresponding to "drop in engine oil pressure" on "Nov. 15, 1996"
means that the engine rotational speed Ne was in the range
Ne1.ltoreq.Ne.ltoreq.Ne2, that the lever operating position S was
in the blade left tilt position, that the vehicle speed was in the
range v1.ltoreq.v.ltoreq.v2, and that the tractive force W was in
the range W>W2.
The past frequency (number of occurrences since new vehicle status)
of the currently detected fault (drop in engine oil pressure) is
searched with reference to the history data, a fault frequency code
indicating the frequency of the fault is added to the
aforementioned fault code, the values of the subsidiary operating
parameters (A) engine rotational speed, (B) lever operation
position, (C) vehicle speed, and (D) tractive force at the time the
fault was detected are sensed based on the output of each sensor,
the status code of these subsidiary parameters is generated based
on FIG. 4 from the detected results, and the status code is added
to the aforementioned fault code.
For example, when it is sensed from the detected results of the
sensors that the engine rotational speed Ne is in the range
Ne1.ltoreq.Ne.ltoreq.Ne2, that the lever operating position S is in
the blade left tilt position, that the vehicle speed v is in the
range v>v2, and that the tractive force W is in the range
W1.ltoreq.W.ltoreq.W2, the status code (A) 2 (B) 3 (C) 3 (D) 2 is
generated. When it is found that a fault indicating a drop in
engine oil pressure has occurred 7 times in the past, the
transmission data that are generated consist of a fault occurrence
status code 7 (times) and the status code (A) 2 (B) 3 (C) 3 (D) 2
in addition to the fault code "0001" indicating a drop in engine
oil pressure (see step 102 in FIG. 1 and FIG. 5).
There is then a search with reference to the history data to find
out whether or not the same fault as the currently detected fault
(drop in engine oil pressure) has occurred in a specific period of
time in the past (one month, for example) (step 103).
When it is thus discovered that the currently detected fault has
not occurred within the past specific period of time, snapshot data
of the subsidiary operating parameters around the point in time at
which the fault was detected are generally considered useful data
for monitoring faults, and the process moves on to the next step
104. In step 104, a determination is made as to whether or not the
currently detected fault is included in a list of unnecessary items
in the host computer 51. Here, the list of unnecessary items is a
list of predetermined faults (predetermined as initial drawbacks)
for each vehicle. When faults contained in this list are detected,
there is no need to transmit snapshot data for the fault to the
monitoring station 20.
When the currently detected fault is not in the list of unnecessary
items, snapshot data SD of the subsidiary operating parameters from
around the point in time at which the fault was detected are added
to the transmission data generated in the aforementioned step 102,
and the transmission data are sent to the monitoring station 20
through the communications A between the vehicles and monitoring
station.
The snapshot data SD are described here. Using the subsidiary
operating parameter (A) engine rotational speed Ne as an example,
as shown in FIG. 6, the snapshot data would be the continuous data
of the values for the engine rotational speed Ne from 10 minutes
before the point in time t0 at which the fault was detected until 5
minutes after the point in time t0 at which the fault was detected.
Data from the past 10 minutes of the operating parameters of the
vehicle 10 should always be stored in the prescribed memory so as
to ensure that such snapshot data SD can be retrieved at the
desired time.
The transmission data that are sent to the monitoring station 20
are obtained from a protocol in which, as shown in FIG. 5, first a
fault code (0001), then a fault occurrence code (7 times), then a
status code ((A) 2 (B) 3 (C) 3 (D) 2), and finally the snapshot
data SD are added.
The aforementioned data are sent from the monitoring station 20
through communications J and the communications in the global net
50 to the host computer 51 (step 105).
When it is determined that the currently detected fault has
occurred in a specific past period of time (step 103 determination
YES) in the aforementioned step 103, or the currently detected
fault is included in the list of unnecessary items in the
aforementioned step 104 (step 104 determination YES), it is
determined that snapshot data corresponding to the detected fault
would not be useful, and the transmission data are sent by the
monitoring station 20 to the host computer 51 without adding the
snapshot data SD.
That is, the transmission data sent by the monitoring station 20 to
the host computer 51 are obtained from a protocol in which, as
shown in FIG. 5, first a fault code (0001), then a fault occurrence
code (7 times), and finally a status code ((A) 2 (B) 3 (C) 3 (D) 2)
are added (step 106).
When a fault is thus detected, the contents of the fault history
data (FIG. 3) are updated based on data related to the detected
fault (fault code, date of occurrence, and status (status code))
(step 107).
When a fault is thus detected, the contents of the snapshot data SD
are updated so as to preserve the values of the operating
parameters from the present to a fixed period of time (10 minutes)
before. The contents of the snap shot data SD are thus sequentially
updated to allow faults to be managed using a low memory volume and
to ensure the prompt retrieval of snapshot data SD (step 108).
The controller for the vehicle 10 determines whether or not a
request command signal for snapshot data SD described below has
been input from the monitoring station 20, and when no request
command has been input, the procedure moves again to step 101, and
the same procedure is repeated (step 109). When a request command
for snapshot data SD has been input from the monitoring station 20,
snapshot data SD corresponding to the fault detected in step 101
are transmitted to the monitoring station 20 (step 110).
The process on the host computer 51 side until the request command
for snapshot data SD is sent is described below with reference to
FIG. 2.
As shown in FIG. 2, the host computer 51 receives transmission data
in the state shown in FIG. 5 from vehicles in the field work site
30 and from all vehicles delivered throughout the world (step
201).
The host computer 51 searches to find out the percentage of all
vehicles throughout the world in which the fault (drop in engine
oil pressure) indicated by the transmission data has occurred,
based on the contents of the transmission data that have been
received, such as the transmission data shown in FIG. 5 sent from
vehicle 10.
Specifically, x/NT is calculated, where NT is the number of the
same type of vehicles as vehicle 10 which have been delivered, and
x is the number of times in the past a drop in engine oil pressure
has occurred, including the current fault detection (step 202).
It is then determined whether or not the x/NT calculated in the
aforementioned step 202 is greater than a specific threshold value
(step 203). When x/NT is greater than the aforementioned threshold
value, snapshot data SD corresponding to the currently detected
fault (drop in engine oil pressure) are not considered useful data
for monitoring faults, and the fault (drop in engine oil pressure)
is placed in the list of unnecessary items. Thus, when a fault
indicating a drop in engine oil pressure is included in the list of
unnecessary items, the determination in step 104 in FIG. 1 is NO
even if a fault indicating a drop in engine oil pressure in vehicle
10 is subsequently detected, and there is no need to add the
snapshot data SD to the transmission data (step 204).
When a type of fault requiring no snapshot data SD transmission is
newly added to the list of unnecessary items, the list of
unnecessary items with updated contents is transmitted from the
host computer 51 through the communications in the global net 50
and communications J to the monitoring station 20, and is
transmitted from the monitoring station 20 through the
communications A between vehicles and monitoring station to the
vehicle 10 (step 205).
Meanwhile, when it is determined that x/NT is below the
aforementioned threshold value in the aforementioned step 203, it
is concluded that the snapshot data SD corresponding to the
currently detected fault (drop in engine oil pressure) would be
useful in monitoring faults, the procedure moves on to step 206,
and the process for determining whether or not snapshot data SD
should be requested of the vehicle 10 is then carried out.
FIG. 7 shows the distribution of status codes used to determine
whether or not snapshot data SD should be requested.
This status code distribution is generated for each type of vehicle
and each type of fault occurring in the vehicles.
The status code distribution in FIG. 7 is the status code
distribution produced for a fault indicating a drop in engine oil
pressure occurring in a bulldozer vehicle (including vehicle
10).
The horizontal axis of the status code distribution is status code
Cd, and the vertical axis is the fault (drop in engine oil
pressure) frequency N. The frequency N is the number of faults
produced in the same type of bulldozer delivered throughout the
world.
Here, the contents of the status code Cd indicated in the
transmission data for an engine oil pressure drop fault transmitted
from vehicle 10, which is a bulldozer, are (A) 2 (B) 3 (C) 3 (D) 2,
and since this corresponds to Cd8 on the horizontal axis, the
status code distribution is updated so that the frequency N8
corresponding to the status code Cd8 increases +1 (step 206).
A threshold value a by which the magnitude of the frequency N is
determined in binary fashion is established for the status code
distribution to determine whether or not snapshot data SD should be
requested.
For example, the fault frequency is N5 when the status code Cd5 is
(A) 1 (B) 2 (C) 3 (D) 2, and since this is greater than the
aforementioned threshold value .alpha. (step 207 determination NO),
there are a great many cases where a fault occurs with a status
code Cd5. It is concluded that the snapshot data SD at this time
would not be useful data, and it is determined that no snapshot
data SD should be requested. The procedure then returns to step
201.
In contrast, the fault frequency is N8 when the status code Cd8 is
(A) 2 (B) 3 (C) 3 (D) 2, and since this is below the aforementioned
threshold value .alpha. (step 207 determination YES), there are
very few cases where a fault occurs with a status code Cd8. It is
concluded that snapshot data SD at this time would be useful data,
and it is determined that snapshot data Sd should be requested. A
request command to transmit snapshot data SD from around the time
the fault occurred in the vehicle 10 from which the transmission
data with the status code Cd8 has been transmitted is sent from the
host computer 51 through the communications in the global net 50
and the communications J to the monitoring station 20. The request
command is then transmitted from the monitoring station 20 through
the communications A between the vehicles and monitoring station to
the vehicle 10 (step 208).
When the controller for the vehicle 10 determines that a request
command signal for snapshot data SD has been input from the
monitoring station 20 in step 109 in FIG. 1, the snapshot data SD
is transmitted through the monitoring station 20 to the host
computer 51 in step 110.
When transmission data to which snapshot data SD has already been
added are received in step 201 in FIG. 2, no process for generating
a snapshot data request command is required in steps 207 and
208.
As described above, transmission data in which a status code has
been added to a fault code are transmitted to the host computer 51,
making it possible to more accurately determine whether or not
snapshot data SD should be requested on the vehicle side from the
status code distribution based on the status code. Fault history
data are prepared on the vehicle side, the fault history data are
compared with the currently detected fault, and a determination is
made, allowing it to be more accurately determined whether or not
snapshot data SD for the fault should be transmitted to the host
computer side.
Thus, only snapshot data SD that are necessary for monitoring
faults are transmitted to the host computer 51, so that faults can
be more accurately monitored on that basis. Furthermore, since only
snapshot data SD necessary for monitoring faults are collected, the
amount of data and the memory storage volume of the host computer
51 can be kept to the minimum necessary levels.
The present embodiment assumed a case in which snapshot data for
vehicles delivered throughout the world the collected in the host
computer 51, but the scope of data that are collected can be set to
any desired magnitude. For example, the function of the host
computer shown in FIG. 2 can be assumed by the computer 21 of the
monitoring station 20 used for the comprehensive control of the
field work site 30, and the snapshot data SD for the vehicles
present in the field work site can be collected in the monitoring
station 20 to determine the maintenance periods for the vehicles in
the field work site 30 and to issue commands for vehicle emergency
stops and the like.
* * * * *